so your standby light stays on but clicking it doesn't activate the power? What about when you press the eject button? It usually also activates the power - it could just be a faulty switch. However if neither of those works, then I'm not sure. It certainly sounds more serious.

I've never really looked at the buttins, but I would assume they're simply cable linked back to the main board. Check the connections there. The fact that the LED lights up over the buttons at least means there's nothing terribly wrong with your power supply.

Did it just stop working, or did you take it apart/move it/ dance on it recently?